This invention relates, in general, to electronics and, more particularly, to methods of manufacturing semiconductor components.
Semiconductor devices such as, for example, transistors in semiconductor components are manufactured using lithographic techniques. It is difficult to utilize conventional lithographic techniques to manufacture features with dimensions of less than 180 nanometers (nm). Accordingly, new lithographic techniques have been developed to more reliably manufacture sub-quartermicron features. As an example, Extreme Ultra-Violet Lithography (EUVL) can be used to manufacture features with dimensions of less than approximately 0.25 microns.
EUVL uses extreme ultra-violet radiation having a wavelength in the range of 4 to 25 nm to carry out projection imaging. EUVL masks are reflective in nature and are not transmissive like masks for other lithographic technologies such as conventional optical photolithography, SCattering with Angular Limitation Projection Electron beam Lithography (SCALPEL) or X-Ray Lithography (XRL). EUVL masks comprise a patterned EUV radiation absorber on top of a multi-layered film that is reflective at EUV wavelengths.
Radiation absorbers in EUVL masks have been fabricated using a two-layer process that involves a repair buffer layer of silicon dioxide and a radiation absorbing layer of aluminum-copper, titanium nitride, or the like. One problem with this two-layer process is the difficulty in patterning the repair buffer layer without damaging the underlying reflective multi-layered film. The buffer layer can be patterned with a reactive ion etching technique, but a high etch selectivity to the underlying multi-layered film is difficult to achieve. A wet etch to pattern the buffer layer can result in an undercutting of the buffer layer beneath the patterned absorber layer, and this undercutting produces other problems.
Accordingly, a need exists for an improved method of manufacturing a semiconductor component having submicron features. If an EUVL process is used in the manufacturing method, the EUVL masks should be substantially defect free, and the peak reflectivity and bandpass at the EUV wavelengths should remain unchanged before and after the patterning of the radiation absorbing layer.